Temperature-Dependent Sex Determination of Green Turtle, Chelonia Mydas, in the Andaman Sea

Abstract

A study on the effect of incubation temperature on sex determination of green turtle, Chelonia mydas, was conducted at Hu-Yong Island, a member of the Similan Islands National Park, in the Andaman Sea. Five nests were collected in March 2009 and relocated to the nesting area. Incubation temperatures from each nest were recorded every 30 minutes using temperature data loggers fixed into the middle of each nest. Sexes of dead hatchlings were determined using a tissue histological method. The results showed that the incubated temperature of all nests ranged between 27.96 – 35.86 OC, while the mean temperatures taken during the middle third period of each nest ranged from 29.11 ± 0.41OC to 30.67 ± 0.73OC. The warmest incubation temperature (30.67 ± 0.73oC) produced 94.12% female turtles, while the coolest incubation temperature (29.11 ± 0.41oC) produced 63.64% females. Thesex ratio of the green turtle at Hu-Yong Island during dry season was 4 females to 1 male.